Here’s something you may not know about dolphins, aside from their enormous intelligence and tendency to kill for fun (seriously: dolphins are thrillkillers); when a dolphin suffers a shark bite, it feels little pain, doesn’t lose a ton of blood, doesn’t get infected, and in fact barely even leaves a scar.

Yes, dolphins do, in fact, have a healing factor. Actually, it’s a mix of different properties that luck out. For example, dolphin blubber is loaded with organohalogens, which are great for offing microbes and other diseases. Part of the reason it doesn’t bleed out is that blood naturally moves away from the skin when they dive. The no-scars thing, on the other hand, has the explanation of “holy crap that’s awesome, but we have no idea how it works.”